Secondary battery

ABSTRACT

A secondary battery including an electrode assembly, the electrode assembly including a separator between a positive electrode and a negative electrode; current collectors, the current collectors being electrically connected to the positive electrode and the negative electrode, respectively; a case, the case accommodating the electrode assembly and the current collectors; a cap plate, the cap plate coupled to an opening in the case; and an insulating film, the insulating film insulating the electrode assembly and the electrode collectors from the case, wherein the insulating film includes a protuberance pattern on at least one surface thereof to compensate for vibration of the electrode assembly current collectors with respect to the case.

BACKGROUND

1. Field

Embodiments relate to a secondary battery.

2. Description of the Related Art

A secondary battery is a rechargeable battery. Secondary batteries maybe used in portable electronic devices, e.g., cellular phones,notebooks, and camcorders. Secondary batteries may also be used to,e.g., drive electric vehicles or hybrid electric vehicles.

The secondary battery may have a structure in which an electrodeassembly having a positive electrode, a negative electrode, and aseparator that are wound to form a jelly roll structure. The electrodeassembly may be installed in the secondary battery through an opening ofa case thereof. The opening may be covered by a cap plate. A currentcollector may be electrically connected to an end of the electrodeassembly and an electrode terminal in the cap plate. Thus, when anexternal terminal is connected to the electrode terminal of the capplate, current generated by the electrode assembly may be supplied tothe external terminal through the current collector and the cap plate.

The current collector may be welded to a corresponding electrode of theelectrode assembly so as to create a current path and to support thejelly roll structure.

SUMMARY

Embodiments are directed to a secondary battery, which representsadvances over the related art.

It is a feature of an embodiment to provide a secondary battery havinghigh durability against vibration.

At least one of the above and other features and advantages may berealized by providing a secondary battery including an electrodeassembly, the electrode assembly including a separator between apositive electrode and a negative electrode; current collectors, thecurrent collectors being electrically connected to the positiveelectrode and the negative electrode, respectively; a case, the caseaccommodating the electrode assembly and the current collectors; a capplate, the cap plate coupled to an opening in the case; and aninsulating film, the insulating film insulating the electrode assemblyand the electrode collectors from the case, wherein the insulating filmincludes a protuberance pattern on at least one surface thereof tocompensate for vibration of the electrode assembly current collectorswith respect to the case.

The secondary battery may further include at least one electrodeterminal electrically connected to at least one of the currentcollectors and protruding through the cap plate.

A shape of the insulating film may correspond to shapes of the electrodeassembly and the current collectors.

A shape of the surface of the insulating film with the protuberancepattern thereon may correspond to shapes of the electrode assembly andthe current collectors.

The protuberance pattern of the insulating film may be an embossedpattern.

The protuberance pattern of the insulating film may have a straight lineshape.

The protuberance pattern of the insulating film may be a corrugatedpattern.

The case may include a pair of first walls, the pair of first wallsbeing parallel to a breadth direction of the cap plate and facing eachother, a pair of second walls, the pair of second walls being parallelto a length direction of the cap plate, and a third wall, the third wallfacing the cap plate and being disposed on a bottom of the case.

The insulating film may be disposed on inside surfaces of the pair offirst walls, the pair of second walls, and the third wall.

A thickness of the insulating film disposed adjacent to the third wallmay be thicker than the thickness of the insulating film disposedadjacent to the pair of second walls.

The protuberance pattern of the insulating film may be disposed adjacentto at least the pair of first walls.

The protuberance pattern of the insulating film may be disposed adjacentto at least the pair of first walls and the third wall.

The protuberance pattern of the insulating film may be disposed adjacentto at least the third wall.

The protuberance pattern of the insulating film may be disposed adjacentto at least the pair of second walls.

The protuberance pattern of the insulating film may be disposed adjacentto the pair of second walls so that the shape of the surface of theinsulating film with the protuberance pattern thereon corresponds to theshape of the curved portion of the electrode assembly.

A thickness of the insulating film disposed adjacent to the pair offirst walls may be thicker than a thickness of the insulating filmdisposed adjacent to the pair of second walls.

A thickness of the insulating film disposed adjacent to the pair offirst walls and the third wall may be thicker than the thickness of theinsulating film disposed adjacent to the pair of second walls.

The thickness of the insulating film may be about 50 μm to about 1 mm.

A height of the protuberance pattern of the insulating film maycorrespond to a height of a curved portion of the electrode assembly.

At least one of the above and other features and advantages may also berealized by providing an electric vehicle or hybrid electric vehicleincluding the secondary battery of an embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages will become more apparent tothose of ordinary skill in the art by describing in detail exemplaryembodiments with reference to the attached drawings, in which:

FIG. 1 illustrates a perspective view of a secondary battery accordingto an embodiment;

FIG. 2 illustrates a cross-sectional view of the secondary battery ofFIG. 1, taken along a line II-II;

FIG. 3 illustrates a partially exploded perspective view of an electrodeassembly, current collectors, a case, and an insulating film of thesecondary battery of FIG. 1;

FIGS. 4A and 4B respectively illustrate top plan views of an insulationfilm uncoupled from an electrode assembly having terminal lead elementsand coupled to the electrode assembly;

FIG. 5 illustrates a partially exploded perspective view of theelectrode assembly, the current collectors, the case, and the insulatingfilm according to another embodiment;

FIG. 6 illustrates a partially exploded perspective view of theelectrode assembly, the current collectors, the case, and the insulatingfilm according to yet another embodiment;

FIG. 7 illustrates a partially exploded perspective view of theelectrode assembly, the current collectors, the case, and the insulatingfilm according to still another embodiment;

FIG. 8 illustrates a partially exploded perspective view of theelectrode assembly, the current collectors, the case, and the insulatingfilm according to still another embodiment;

FIG. 9 illustrates a partially exploded perspective view of theelectrode assembly, the current collectors, the case, and the insulatingfilm according to yet another embodiment;

FIG. 10 illustrates a partially exploded perspective view of theelectrode assembly, the current collectors, the case, and the insulatingfilm according to yet another embodiment; and

FIG. 11 illustrates a cross-sectional view of a secondary batteryaccording to another embodiment.

DETAILED DESCRIPTION

Korean Patent Application No. 10-2009-0110365, filed on Nov. 16, 2009,in the Korean Intellectual Property Office, and entitled: “SecondaryBattery,” is incorporated by reference herein in its entirety.

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawings; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art.

In the drawing figures, the dimensions of layers and regions may beexaggerated for clarity of illustration. It will also be understood thatwhen a layer or element is referred to as being “on” another element, itcan be directly on the other element, or intervening elements may alsobe present. In addition, it will also be understood that when an elementis referred to as being “between” two elements, it can be the onlyelement between the two elements, or one or more intervening elementsmay also be present. Like reference numerals refer to like elementsthroughout.

It will be understood that when an element is referred to as being“connected to” or “coupled to” another element, it may be directlyconnected or coupled to the other element or intervening elements may bepresent, unless otherwise explicitly stated. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

FIG. 1 illustrates a perspective view of a secondary battery 1 accordingto an embodiment. FIG. 2 illustrates a cross-sectional view of thesecondary battery 1 taken along a line II-II of FIG. 1. FIG. 3illustrates a partial exploded perspective view of an electrode assembly10, current collectors 40 a and 40 b, a case 34, and an insulating film200 of the secondary battery 1 of FIG. 1.

Referring to FIGS. 1 through 3, the secondary battery 1 may include theelectrode assembly 10, electrode terminals 21 and 22, the insulatingfilm 200, and the case 34. The case 34 may accommodate the electrodeassembly 10. The electrode assembly 10 may be electrically connected toan outside device via the electrode terminals 21 and 22. The insulatingfilm 200 may be disposed between the electrode assembly 10 and the case34. The insulating film 200 may perform an insulating function betweenthe electrode assembly 10 and the case 34 so as to compensate forvibration of the electrode assembly 10 and the electrode terminals 21and 22.

The electrode assembly 10 may include a positive electrode 11, anegative electrode 12, and a separator 13. The positive electrode 11,the negative electrode 12, and the separator 13 may be wound such thatthe separator 13 is disposed between the positive electrode 11 and thenegative electrode 12. The positive electrode 11 may include a positiveelectrode uncoated unit 11 a and a positive electrode coated unit 11 a.The negative electrode 12 may include a negative electrode uncoated unit12 a and a negative electrode coated unit 12 b. The positive electrodeuncoated unit 11 a and the negative electrode uncoated unit 12 a mayinclude a metal foil current collector on which an active material isnot coated. The positive electrode coated unit 11 b and the negativeelectrode coated unit 12 b may include a metal foil current collector onwhich an active material is coated. The positive electrode uncoated unit11 a may be formed at a side of the positive electrode 11 in alongitudinal direction of the positive electrode 11. The negativeelectrode uncoated unit 12 a may be formed at a side of the negativeelectrode 12 in a longitudinal direction of the negative electrode 12.In an implementation, the electrode assembly 10 may include the positiveelectrode 11, the negative electrode 12, and the separator 13 wound in acylindrical shape. Then the wound positive electrode 11, negativeelectrode 12, and separator 13 may be pressed. The electrode assembly 10may be pressed into a plate shape so as to form a flat portion 18 and acurved portion 19, as illustrated in FIG. 3. The flat portion 18 may beformed by winding the positive electrode 11, the negative electrode 12,and the separator 13 and then pressing the positive electrode 11, thenegative electrode 12, and the separator 13 so as to planarize a portionof a circumference of the electrode assembly 10. The curved portion 19may be disposed at ends of the flat portion 18, both of which may beformed by pressing the electrode assembly 10.

A positive electrode current collector unit 40 a may be coupled to thepositive electrode uncoated unit 11 a of the electrode assembly 10 by,e.g., welding. The positive electrode current collector unit 40 a may beelectrically connected to a positive electrode terminal 21 via a leadelement 28. Thus, the positive electrode terminal 21 may be connected tothe positive electrode 11 of the electrode assembly 10 via the leadelement 28 and the positive electrode current collector unit 40 a. Anegative electrode current collector 40 b may be electrically connectedto a negative electrode terminal 22 via another lead element 28. Thus,the negative electrode terminal 22 may be connected to the negativeelectrode 12 of the electrode assembly 10 via the other lead element 28and the negative electrode current collector 40 b. An insulating element26 may be disposed between the lead elements 28 and a cap plate 20 inorder to insulate these components from each other. The lead elements 28may include current collecting lead elements 28 b attached to respectivecurrent collectors 40 a and 40 b and terminal lead elements 28 aattached to respective electrode terminals 21 and 22.

The electrode terminals 21 and 22 may include the positive electrodeterminal 21 and the negative electrode terminal 22. The positiveelectrode terminal 21 and the negative electrode terminal 22 may beelectrically connected to the positive electrode 11 and the negativeelectrode 12, respectively, and may protrude outside of the case 34.

The cap plate 20 may be coupled to an end of the case 34. The case 34may have a can shape having an open side. Thus, the open side may besealed by the cap plate 20. The electrode assembly 10 together withelectrolyte may be accommodated in the case 34 through the open side.The cap plate 20 may cover the case 34 such that the electrode terminals21 and 22 are exposed to the outside. An interface between the case 34and the cap plate 20 may be welded using, e.g., a laser, so as to sealthe case 34 in which the electrode assembly 10 together with theelectrolyte are accommodated. The cap plate 20 may have a thin plateshape. An electrolyte inlet 38 a for injecting the electrolyte may beformed in the cap plate 20. A sealing cap 38 may be inserted into theelectrolyte inlet 38 a. A vent element 39 including a groove may beformed in the cap plate 20 so as to be capable of being broken open by apredetermined internal pressure in the case 34.

The insulating film 200 will now be described. Referring to FIG. 1, thecase 34 of the secondary battery 1 may include a pair of first walls Xand X′, a pair of second walls Y and Y′, and a third wall Z. The pair offirst walls X and X′ may be parallel to a breadth direction of the capplate 20 and may face each other. The pair of second walls Y and Y′ maybe parallel to a longitudinal direction of the cap plate 20,perpendicular to the breadth direction, and may face each other. Thethird wall Z may be opposite to and face the cap plate 20 so as toconstitute a bottom of the case 34. The cap plate 20 may be disposed ona Z′ plane. In this case, when, e.g., a rotational and/or vibrationalforce, are applied to the secondary battery 1, since it may not be easyto move the electrode assembly 10 with respect to the second walls Y andY′, i.e., in a direction orthogonal thereto, due to the thickness of theelectrode assembly 10, the electrode assembly 10 may barely move.However, a space may exist between the electrode assembly 10 and thecase 34 with respect to, the pair of first walls X and X′ or the thirdwall Z, i.e., in a direction orthogonal thereto. Accordingly, theelectrode assembly 10 may be affected by the, e.g., vibrational and/orrotational force. That is, the electrode assembly 10 may move withrespect to the pair of first walls X and X′ or the third wall Z of thecase 34. If the secondary battery 1 is a medium or large-sized secondbattery, a relatively large space may exist between the electrodeassembly 10 and the case 34, such that the electrode assembly 10 may beseriously affected by, e.g., vibration or rotation. As illustrated inFIGS. 2 and 3, the insulating film 200 may surround the electrodeassembly 10 and the current collectors 40 a and 40 b. In this regard,the insulating film 200 may include, e.g., an unevenness portion. Theunevenness portion may be in the form of peaks and valleys, i.e., apattern of protuberances extending from areas that are recessed relativethereto (hereinafter “protuberance pattern 200 a”). The protuberancepattern 200 a may perform an insulating function and may also compensatefor vibration of the electrode assembly 10, the current collectors 40 aand 40 b, and the lead elements 28 with respect to the case 34. In thiscase, referring to FIG. 3, a corrugated protuberance pattern may beformed on a surface of the insulating film 200. The protuberance patternmay have elastic properties such that movement of the electrode assembly10 and the current collectors 40 a and 40 b may be compensated for,i.e., absorbed. In an implementation, if the protuberance pattern 200 ais formed on the insulating film 200 and facing the case 34, theinsulating film 200 may react more elastically than when compressed bythe electrode assembly 10 and the current collectors 40 a and 40 b.

Although not illustrated, a height of the protuberance pattern 200 a ofthe insulating film 200 disposed on the third wall Z may correspond tothe height of the curved portion 19 of the electrode assembly 10. Thatis, if a space exists between the electrode assembly 10 and the case 34due to a curved surface of the curved portion 19, the height of theprotuberance pattern 200 a may increase, thereby compensating forvibration of the electrode assembly 10.

Operation of the insulating film 200 including the protuberance pattern200 a will now be described with reference to FIGS. 4A and 4B. FIGS. 4Aand 4B respectively illustrate top plan views of the insulation film 200uncoupled from the electrode assembly 10 and the insulation film 200coupled to the electrode assembly 10. Referring to FIGS. 4A and 4B, theprotuberance pattern 200 a, which may be formed on the surface of theinsulating film 200, may compress both sides of terminal lead elements28 a of the lead elements 28 and may be elastically coupled to theelectrode assembly 10. Accordingly, the terminal lead elements 28 a maybe elastically fixed, thereby compensating for vibration of the terminallead elements 28 a and the electrode assembly 10. In an implementation,the insulating film 200 may be formed on the pair of first walls X, X′,the pair of second walls Y, Y′, and/or the third walls Z in order toinsulate the electrode assembly 10 and/or the current collectors 40 aand 40 b from the case 34. In an implementation, the insulating film 200including the protuberance pattern 200 a may be formed on the pair offirst walls X, X′ and the third wall Z where relatively large spaces mayexist, thereby compensating for the vibration of the terminal leadelements 28 a and the electrode assembly 10.

In an implementation, the protuberance pattern 200 a of the insulatingfilm 200 may only be disposed between the current collectors 40 a and 40b and the pair of first walls X, X′. In another implementation, theprotuberance pattern 200 a of the insulating film 200 may be disposedbetween the current collectors 40 a and 40 b and the pair of first wallsX, X′ as well as between the current collectors 40 a and 40 b and thethird wall Z. In still another implementation, protuberance pattern 200a of the insulating film 200 may only be disposed between the currentcollectors 40 a and 40 b and the third wall Z.

In this regard, the insulating film 200 including the protuberancepattern 200 a on the pair of first walls X, X′ and the third wall Z maynot limit inclusion of an insulating film including no protuberancepattern on the pair of second walls Y, Y′.

Further, the insulating film 200 on the pair of first walls X, X′ andthe third wall Z where relatively large spaces may exist may have asubstantial thickness, so that the protuberance pattern 200 a mayeffectively compensate for the vibration of the electrode assembly 10.

In an implementation, a thickness of the insulating film 200 adjacent tothe pair of first walls X, X′ may be thicker than a thickness of theinsulating film 200 adjacent to the pair of second walls Y, Y′. Inanother implementation, the thickness of the insulating film 200adjacent to the pair of first walls X, X′ and the third wall Z may bethicker than the thickness of the insulating film 200 adjacent the pairof second walls Y, Y′. In yet another implementation, the thickness ofthe insulating film 200 adjacent to the third wall Z may be thicker thanthe thickness of the insulating film 200 adjacent to the pair of secondwalls Y, Y′.

The thickness of the insulating film 200 may be, e.g., about 50 μm toabout 1 mm. The insulating film 200 including the protuberance pattern200 a may be formed along a wall of the case 34 or may correspond to ashape of, e.g., the current collectors 40 a and 40 b and/or theelectrode assembly 10.

However, the position and shape of the protuberance pattern 200 a formedof the insulating film 200 are not limited to any particular form orarrangement described above. Modifications of the insulting film 200will now be described with reference to FIGS. 5 through 8.

FIG. 5 illustrates a partially exploded perspective view of theelectrode assembly, the current collectors, the case, and the insulatingfilm according to another embodiment. Referring to FIG. 5, theprotuberance pattern 300 a may be formed on a surface of an insulatingfilm 300 facing the current collectors 40 a and 40 b as well as on asurface of the insulating film 300 facing the case 34. In other words,the protuberance pattern 300 a may be formed on both surfaces of theinsulating film 300, thereby more effectively compensating for vibrationof the electrode assembly 10 in the case 34. Although not illustrated,in an implementation the protuberance pattern 300 a may be formed onlyon the surface of the insulating film 300 facing the case 34.

FIG. 6 illustrates a partially exploded perspective view of theelectrode assembly, the current collectors, the case, and the insulatingfilm according to yet another embodiment. Referring to FIG. 6, theprotuberance pattern 400 a may be, e.g., corrugated with an additionalzig-zag or saw-tooth pattern on the corrugations. In particular, theprotuberance pattern 400 a may include further peaks and valleys on thepeaks of the base pattern. Although not illustrated, in animplementation, the protuberance pattern 400 a may be formed on bothsurfaces, i.e., on opposing surfaces, of the insulating film 400, asdescribed above.

FIGS. 7 and 8 illustrate partially exploded perspective views of theelectrode assembly, the current collectors, the case, and the insulatingfilm according to other embodiments. Referring to FIGS. 7 and 8,protuberance patterns 500 a and 600 a of insulating films 500 and 600,respectively, may be, e.g., embossed. In particular, the protuberancepattern 500 a may include rows of hemispherical protuberances on theinsulating film 500. In another implementation, the protuberance pattern600 a may include rows of pyramidal protuberances on the insulating film600. Although not illustrated, in other implementations, theprotuberance patterns 500 a and 600 a may be formed on both surfaces ofthe insulating films 500 and 600, respectively, as described above.

FIG. 9 illustrates a partially exploded perspective view of theelectrode assembly, the current collectors, the case, and the insulatingfilm according to still another embodiment. Referring to FIG. 9, theprotuberance pattern 700 a may be formed in the insulating film 700adjacent to the pair of second walls Y, Y′. However, the position of theprotuberance pattern 700 a is not limited thereto. The position of theprotuberance pattern 700 a may be applied to the embodiments describedwith reference to FIGS. 5 through 8 and various modifications thereof.

FIG. 10 illustrates a partially exploded perspective view of theelectrode assembly, the current collectors, the case, and the insulatingfilm according to still another embodiment. Referring to FIG. 10, theprotuberance pattern 800 a may be formed on the insulating film 800adjacent to a part of the pair of second walls Y, Y′. In particular, theelectrode assembly 10 may be pressed into a plate shape so as to formthe flat portion 18 and the curved portion 19. Thus, a relatively largerspace may exist in a portion where the curved portion 19 and the case 34contact each other. Accordingly, the protuberance pattern 800 a of theinsulating film 800 may be formed on the pair of second walls Y, Y′ inan area corresponding only to the curved portion 19 to thereby fill thespace.

Although various modifications of the protuberance pattern 200 a, 300 a,400 a, 500 a, 600 a, 700 a, and 800 a are described with reference toFIGS. 3 through 10, the shapes thereof are not limited thereto. Theprotuberance pattern 200 a, 300 a, 400 a, 500 a, 600 a, 700 a, and 800 amay have various shapes in order to compensate for the vibration of theelectrode assembly 10 and/or the current collectors 40 a and 40 b. Forexample, the protuberance pattern 200 a, 300 a, 400 a, 500 a, 600 a, 700a, and 800 a may be formed on a part of the pair of first walls X, X′ orthe third wall Z.

Terminal holes 21 a and 22 a may be formed through the cap plate 20. Theterminal holes 21 a and 22 a may include a positive electrode terminalhole 21 a and a negative electrode terminal hole 22 a. The positiveelectrode terminal 21 may protrude through the positive electrodeterminal hole 21 a. The negative electrode terminal 22 may protrudethrough the negative electrode terminal hole 22 a. An upper gasket 25and a lower gasket 27 may be disposed between the cap plate 20 and theelectrode terminals 21 and 22 so as to insulate the cap plate 20 fromthe electrode terminals 21 and 22. The lower gasket 27 may be insertedinto the respective terminal holes 21 a and 22 a so as to be disposed ata lower portion of the cap plate 20. The upper gasket 25 may beinstalled at an upper portion of the cap plate 20. A washer 24 forbuffering a clamping force may be installed on the upper gasket 25.Screw threads may be formed on the positive electrode terminal 21 andthe negative electrode terminal 22, respectively, so as to be coupled toa nut 29. The nut 29 may support the electrode terminals 21 and 22 fromabove.

However, the embodiments are not limited thereto. In an implementation,the electrode terminals 21 and 22 may be formed as rivets. In such case,a portion of the electrode terminals 21 and 22 may protrude through theterminal holes 21 a and 22 a. The upper gasket 25 may be inserted intothe terminal holes 21 a and 22 a and surround a portion of the electrodeterminals 21 and 22 that protrudes through the terminal holes 21 and 22a. The portion of the electrode terminals 21 and 22 that protrudes maybe compressed so that the electrode terminals 21 and 22 are widelyflattened. Thus, the electrode terminals 21 and 22 may be fixed to thecap plate 20.

According to the embodiments, the secondary battery 1 may be alithium-ion battery, but is not limited thereto. The secondary battery 1may be, e.g., a nickel-cadmium secondary battery, a nickel-hydrogensecondary battery, or a lithium battery.

According to the embodiments, the secondary battery 1 may have a square,i.e., prismatic or hexahedral, shape, as illustrated in FIGS. 1 through3, but is not limited thereto. The secondary battery 1 may be, e.g., acylindrical battery or a pouch type battery.

The positive electrode 11, the current collectors 40 a and 40 b, and thelead element 28 that are electrically connected to each other may beformed of the same material, e.g., aluminum (Al). In this case, apositive electrode short circuiting induction element (not illustrated)may be formed of the same material as that of the lead element 28, e.g.,aluminum (Al). The lead element 28 may be integrally formed with thepositive electrode short circuiting induction element or may beconnected to the positive electrode short circuiting induction elementby, e.g., welding.

The negative electrode 12, the current collectors 40 a and 40 b, and thelead element 28 that are electrically connected may be formed of thesame material, e.g., copper (Cu). In this case, a negative electrodeshort circuiting induction element (not illustrated) may be formed ofthe same material as that of the lead element 28, e.g., copper (Cu). Thelead element 28 may be integrally formed with the negative electrodeshort circuiting induction element or may be connected to the negativeelectrode short circuiting induction element by, e.g., welding.

An internal space 14 may be formed in the center of the electrodeassembly 10 by compressing the electrode assembly 10 into a flat shapewhile the electrode assembly 10 is wound. Each of the current collectors40 a and 40 b may include a support protrusion 42 inserted into theinternal space 14. The current collectors 40 a and 40 b may also includean attachment plate 41 coupled to a lateral end of the electrodeassembly 10 so as to compress the positive electrode uncoated unit 11 aand the negative electrode uncoated unit 12 a and welded thereto.

The support protrusion 42 may extend from a center of a width directionof the respective current collector 40 a or 40 b along a longitudinaldirection of the current collector 40 a or 40 b. The height of thesupport protrusion 42 may correspond to the height of the internal space14 of the electrode assembly 10.

The support protrusion 42 may be inserted into the internal space 14 ofthe electrode assembly 10 so as to support the electrode assembly 10,thereby preventing contact errors between the electrode assembly 10 andthe current collectors 40 a and 40 b caused by external shocks. Thesupport protrusion 42 may support the electrode assembly 10 in a widthdirection of the internal space 14 as well as in a longitudinaldirection of the internal space 14, thereby stably supporting theelectrode assembly 10.

The attachment plates 41 may be disposed at both lateral ends of thesupport protrusion 42. The attachment plates 41 may be coupled tolateral end surfaces of the electrode assembly 10 so as to compress thepositive electrode uncoated unit 11 a and the negative electrodeuncoated unit 12 a. The lateral end surface is a surface perpendicularto a central axis when the electrode assembly 10 is wound.

Thus, the attachment plates 41 may contact the respective positiveelectrode uncoated unit 11 a and negative electrode uncoated unit 12 aover a relatively large area. The attachment plate 41 may be attached tothe lateral end surface of the electrode assembly 10 by, e.g., laserwelding. When the attachment plate 41 is attached by laser welding, athickness of each of the current collector units 40 a and 40 b may bethicker than in a case where the attachment plate 41 is attached byultrasonic welding, thereby reducing a resistance of each of the currentcollector units 40 a and 40 b.

Since the current collectors 40 a and 40 b may be fixed to lateral endsof the respective positive electrode uncoated unit 11 a and the negativeelectrode uncoated unit 12 a, an entire output of the electrode assembly10 may be increased by reducing an area of each of the positiveelectrode uncoated unit 11 a and negative electrode uncoated unit 12 aand increasing an area of each of the coated units 11 b and 12 b.

However, the structure of the secondary battery 1 is not limitedthereto. According to another embodiment, the upper gasket 25, theinsulating element 26, and the lower gasket 27 for electricallyseparating the positive electrode 11 or the negative electrode 12 fromthe cap plate 20 may not be installed in one of the positive electrodeterminal 21 or the negative electrode terminal 22. For example, theupper gasket 25 and the lower gasket 27 may not be installed between thepositive electrode terminal 21 and the cap plate 20; and the insulatingelement 26 may not be installed between the lead element 28 and the capplate 20 at the positive electrode terminal 21. In this case, thepositive electrode terminal 21 may pass directly through the positiveelectrode terminal hole 21 a so as to contact the cap plate 20 withoutthe upper gasket 25 and the lower gasket 27. In addition, the leadelement 28 may contact the cap plate 20 directly. In this case, the capplate 20 and the case 34 may have the same polarity as that of thepositive electrode terminal 21.

FIG. 11 illustrates a cross-sectional view of a secondary battery 1′according to another embodiment. Comparing the secondary battery 1′ withthe secondary battery 1 of FIG. 1, FIG. 11 illustrates a case where theupper gasket 25, the insulating element 26, and the lower gasket 27 forelectrically separating a positive electrode terminal (not visible) or anegative electrode terminal 122 from a cap plate 130 are not installedin a positive electrode terminal hole (not visible) or a negativeelectrode terminal hole 122 a.

Like reference numerals in FIGS. 1 and 11 denote like elements, and thusrepeated description thereof will be omitted. The secondary battery 1 isreferred to in order to understand the secondary battery 1′.

Referring to FIG. 11, in the secondary battery 1′, the upper gasket 25and the lower gasket 27 may not be installed between the positiveelectrode terminal and the cap plate 130, and the insulating element 26may not be installed between a lead element 128 and the cap plate 130 atthe positive electrode terminal.

In this case, the positive electrode terminal may pass directly througha positive electrode terminal hole so as to contact the cap plate 130without the upper gasket 25 and the lower gasket 27. In addition, thelead element 128 at the positive electrode terminal may directly contactthe cap plate 130. In this case, the cap plate 130 and a case 134 mayhave the same polarity as that of the positive electrode terminal.

In an implementation, the insulating film 200 including a recess may bedisposed between the electrode assembly 10 and the case 34, like inFIGS. 1, 2, 3, 4A, and 4B. That is, the electrode assembly 10 and thecase 34 may be insulated from each other. As illustrated in FIG. 11, anegative electrode current collector unit 140 b may be electricallyconnected to the negative electrode terminal 122 and insulated from thecase 34. A positive electrode current collector unit 140 a does not haveto be insulated from the case 34. However, in order to prevent shakingand movement of the electrode assembly 10 due to vibration of the case34, the insulating film 200 including the recess corresponding to ashape of the current collector units 140 a or 140 b and/or the electrodeassembly 110 may be included to insulate and/or to compensate for theeffects of vibration.

The secondary battery of an embodiment may be used in an electric orhybrid electric vehicle, e.g., an electric or hybrid electric car, anelectric bicycle, an electric scooter, and the like.

Exemplary embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation.Accordingly, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made without departingfrom the spirit and scope of the present invention as set forth in thefollowing claims.

1. A secondary battery, comprising: an electrode assembly, the electrodeassembly including a separator between a positive electrode and anegative electrode; current collectors, the current collectors beingelectrically connected to the positive electrode and the negativeelectrode, respectively; a case, the case accommodating the electrodeassembly and the current collectors; a cap plate, the cap plate coupledto an opening in the case; and an insulating film, the insulating filminsulating the electrode assembly and the electrode collectors from thecase, wherein the insulating film includes a protuberance pattern on atleast one surface thereof.
 2. The secondary battery as claimed in claim1, further comprising at least one electrode terminal electricallyconnected to at least one of the current collectors and protrudingthrough the cap plate.
 3. The secondary battery as claimed in claim 1,wherein a shape of the insulating film corresponds to shapes of theelectrode assembly and the current collectors.
 4. The secondary batteryas claimed in claim 1, wherein a shape of the surface of the insulatingfilm with the protuberance pattern thereon corresponds to shapes of theelectrode assembly and the current collectors.
 5. The secondary batteryas claimed in claim 1, wherein the protuberance pattern of theinsulating film is an embossed pattern.
 6. The secondary battery asclaimed in claim 1, wherein the protuberance pattern of the insulatingfilm has a straight line shape.
 7. The secondary battery as claimed inclaim 1, wherein the protuberance pattern of the insulating film is acorrugated pattern.
 8. The secondary battery as claimed in claim 1,wherein the case includes: a pair of first walls, the pair of firstwalls being parallel to a breadth direction of the cap plate and facingeach other, a pair of second walls, the pair of second walls beingparallel to a length direction of the cap plate, and a third wall, thethird wall facing the cap plate and being disposed on a bottom of thecase.
 9. The secondary battery as claimed in claim 8, wherein theinsulating film is disposed on inside surfaces of the pair of firstwalls, the pair of second walls, and the third wall.
 10. The secondarybattery as claimed in claim 9, wherein a thickness of the insulatingfilm disposed adjacent to the third wall is thicker than the thicknessof the insulating film disposed adjacent to the pair of second walls.11. The secondary battery as claimed in claim 8, wherein theprotuberance pattern of the insulating film is disposed adjacent to atleast the pair of first walls.
 12. The secondary battery as claimed inclaim 8, wherein the protuberance pattern of the insulating film isdisposed adjacent to at least the pair of first walls and the thirdwall.
 13. The secondary battery as claimed in claim 8, wherein theprotuberance pattern of the insulating film is disposed adjacent to atleast the third wall.
 14. The secondary battery as claimed in claim 8,wherein the protuberance pattern of the insulating film is disposedadjacent to at least the pair of second walls.
 15. The secondary batteryas claimed in claim 8, wherein the protuberance pattern of theinsulating film is disposed adjacent to the pair of second walls so thatthe shape of the surface of the insulating film with the protuberancepattern thereon corresponds to the shape of the curved portion of theelectrode assembly.
 16. The secondary battery as claimed in claim 8,wherein a thickness of the insulating film disposed adjacent to the pairof first walls is thicker than a thickness of the insulating filmdisposed adjacent to the pair of second walls.
 17. The secondary batteryas claimed in claim 8, wherein a thickness of the insulating filmdisposed adjacent to the pair of first walls and the third wall isthicker than the thickness of the insulating film disposed adjacent tothe pair of second walls.
 18. The secondary battery as claimed in claim1, wherein the thickness of the insulating film is about 50 μm to about1 mm.
 19. The secondary battery as claimed in claim 1, wherein a heightof the protuberance pattern of the insulating film corresponds to aheight of a curved portion of the electrode assembly.
 20. An electricvehicle or hybrid electric vehicle including the secondary battery asclaimed in claim 1.